Research is designed to yield new insights into basic mechanisms of heredity in higher organisms. Projects investigate, from several avenues of approach, the nature of cellular structures involved, and the relationships among processes, in homologous chromosome pairing, genetic crossingover, crossover interference, the maintenance of chiasmate association, and chromosome distribution to gametes. Techniques include cytogenetic engineering, laboratory experimental treatment and cytological observations using electron microscopy and the extraordinary light microscope optical systems currently available. The organism selected for study offers a unique combination of excellence of meiotic cytology, an array of available meiotic mutants, morphological chromosome variants and polysomics, a very good genetic map and probability of general applicability of results.